JP4357310B2 - Communication method and communication apparatus for simultaneous connection to a plurality of networks - Google Patents

Description

  The present invention belongs to packet communication technology, and in particular, in a form in which a small network such as a home network is connected to a plurality of external networks, a selection is made as to which of the networks communicates with the outside. Belongs to technology.

  The form in which one communication terminal is connected to a plurality of networks has been mainly performed in order to cope with a failure of a communication line or a device, or to make a communication device redundant. As such redundancy technologies, VRRP (Virtual Router Redundancy Protocol) and ECMP (Equal-Cost Multi-path) technologies have been proposed.

  VRRP is described in IETF RFC2338 (Non-Patent Document 1). One of the two routers connected to a network is operated as the active system, and the remaining one is set as the standby system. By doing so, the router which is the exit of the network is made redundant.

  ECMP refers to a situation where there are a plurality of next hops having the same transfer cost when transferring from a router to a destination in IP (Internet Protocol) routing, and the load on the route can be distributed by implementing the router. Generally, as shown in IETF RFC2991 (non-patent document), hash calculation of IP header information is performed, and traffic is distributed by deciding which route to transfer.

  In recent years, it has been considered to provide various services using IP such as video distribution using IP and IP telephone. Along with this, it is considered that a dedicated IP network suitable for each service provision will be built, and a technology for simultaneously connecting to a plurality of IP networks is required. For example, a content delivery network (CDN) is being studied as a dedicated IP network that delivers high-quality video that cannot be provided on the Internet.

  However, when both the Internet and CDN are used, the convenience is lost if the connection destination network is switched every time it is used. For this reason, it is necessary to connect to a plurality of networks at the same time and use them seamlessly each time they are used. However, the VRRP and ECMP described above are technologies for a case where there are a plurality of routes in order to reach a single destination address, and a plurality of networks cannot be used properly according to the purpose.

  As described above, according to the conventional technique, it is impossible to easily determine a route when simultaneously connected to a plurality of independent networks.

S. Knight et al., "RFC 2238: Virtual Router Redundancy Protocol" April 1998, ftp://ftp.rfc-editor.org/in-notes/rfc2338.txt D. Thaler, C. Hopps, "RFC2991: Multipath Issues in Unicast and Multicast Next-Hop Selection", November 2000, ftp://ftp.rfc-editor.org/in-notes/rfc2991.txt

  A router that transfers an IP (Internet Protocol) packet determines an output destination of the received packet with reference to a route table. The route table may be set in advance in the router or dynamically set by a dynamic routing protocol.

  Dynamic routing protocols include RIP (Routing Information Protocol), OSPF (Open Shortest Path Fast), BGP (Border Gateway Protocol), LAN (Local Area Network) and It is used according to the scale of the network such as ISP (Internet Service Provider) on the Internet.

  In the dynamic routing protocol, the route information of its own network and its router is notified to other networks and other routers. If incorrect route information is notified, Problems can arise. For this reason, it is common for an administrator having knowledge of the network to make settings.

  On the other hand, when connecting to the Internet in general home users or SOHO (Small Office Home Home Office), etc., when the size of the network is relatively small, for example, from one to several terminals Rarely have an administrator with network knowledge to set up a dynamic routing protocol.

  Also, a router that operates a dynamic routing protocol that requires complicated processing is relatively expensive, and such a router is rarely installed. For this reason, in a small-scale network, only the default route is set, and when communicating outside the local network, it is generally set so that all communication goes through the default route. Has been done.

  However, the conventional technique using such a default route cannot connect to an external network using a plurality of lines. That is, even if there are a plurality of lines, one of them is set as a default route and used for connection to an external network, so that the remaining lines are not used.

  In order to solve this, a complicated dynamic routing protocol is operated, or a network administrator specifies a communication destination in advance, determines which line should be used, and sets a route table in the router. There is a problem that it is necessary to perform setting work, and in any case, complicated setting is necessary.

  Here, an example is given of the case where IP is used as a protocol, and the prior art will be described for the case of simultaneous connection to a closed network such as the Internet and an in-house network.

  In this example, it is assumed that a communication apparatus using a conventional technique is connected to the Internet and a closed network via a router 1 and a router 2 as shown in FIG. Assume that IP addresses used in the routers 1 and 2, the conventional communication device, and the closed network are as shown in FIG. 10.

  When using the conventional technology, the default route is set to AAA1 which is the address of the router 1 and the address CCC0 / 24 used in the closed network is transferred to the conventional communication device as the destination address. A routing table as shown in FIG. 11 is set such that the output destination (next hop) is transferred to BBB1, which is the address of router 2. By setting in this way, it is possible to read the destination address of the packet received from the terminal side and transfer it to the output destination according to the routing table.

  That is, it is necessary to set the output destination for the C.C.C.0 / 24 network shown in FIG. As this method, the device administrator sets the address notified in writing from the network administrator in the conventional packet transfer apparatus, or the routing owned by the router 2 using the dynamic routing protocol. I had to be notified of the table.

  Also, when using the dynamic routing protocol, the communication device is notified of the routing information held by the communication device to the Internet side and the closed network side. This affects the routing information of the entire network, and in the worst case, the entire network becomes incapable of communication. For this reason, there has been a problem that the conventional communication terminal requires advanced settings such as setting that is consistent with both the Internet side and the closed network side.

  Also, when the scale of the closed network shown in FIG. 10 is large and a plurality of address blocks are used in the closed network, the scale of the routing table held by the router 2 becomes enormous, and the conventional communication apparatus is There was a problem that it was necessary to have a huge routing table.

  Further, when the closed network shown in FIG. 10 is connected to the Internet, routing information transferred to the Internet is obtained from both the router 1 on the Internet side and the router 2 on the closed network side. It was necessary to operate an advanced routing algorithm based on the dynamic routing protocol for use.

  An object of the present invention relates to a communication apparatus and a communication method for automatically setting a route, and when connecting a network to the outside using a plurality of routes, the conventional technology using a default route uses a plurality of lines to externally The problem is that you cannot connect to the network.

  It is another object of the present invention to solve the problem that an administrator needs to make complicated settings such as communication path determination and routing protocol when connecting to an external network using a plurality of lines. It is.

  It is another object of the present invention to solve the problem of having to store a huge scale routing table by using a dynamic routing protocol.

  It is another object of the present invention to solve the problem that, when incorrect routing information is notified, the entire network may be affected by using a dynamic routing protocol.

In order to achieve the above object, the present invention has the following configuration. That is,
(1) The first communication device and the second communication device are each physically or logically connected to a plurality of networks, and the first communication device and the second communication device perform packet communication via the network. In the communication method, when the first communication device transmits a communication packet, the first communication device identifies the source address of the communication packet, and each address of the device connected to the plurality of networks and the plurality of networks. A search packet that notifies all pairs of identifiers is transmitted toward the destination of the communication packet, and when the second communication device receives the search packet, the first communication device connects to the network from the search packet. The same identification as the network to which the second communication device is connected A proposal that selects at least one set having the address, the address of the first communication device of the selected set as the destination address, and the address connected to the network of the set selected by the second communication device as the source address packets, transmitted over a set of selected networks, the first communication device, when receiving a proposal packet, reads the address of the second communication device described in proposed packet, the first communication The communication packet transmitted from the apparatus to the second communication apparatus is transferred with the address of the read second communication apparatus as the destination.

(2) The communication method according to (1), the search packet are described a set of first address communication device is connected to the network and communication protocols, first by the described communication protocol The communication device notifies the protocol used when communicating with the second communication device on the corresponding network, and the second communication device also reads the communication protocol described in the search packet, and the own device supports it. Communication is performed only for a communication protocol.

( 3 ) In the communication method described in (1) or (2 ) above, the search packet includes a numerical sequence randomly generated by the first communication device, and the second communication device transmits the search packet to the search packet. In the case of reception, the numerical value string is read, and the read numerical value string is described in the proposal packet and transmitted.

( 4 ) The first communication device is physically or logically connected to a plurality of networks, the second communication device connected to the first network, and the third connected to the second network. a communication method for performing communication apparatus and a packet communication, the first communication apparatus, when transmitting a communication packet for communicating with a second communication device, the source address of the communication packet, and the own device has multiple network When the second communication device receives the search packet, the second communication device transmits the search packet from the search packet. A set of addresses and network identifiers that one communication device is connected to the network is read, and a third communication device is connected from the set. Select at least one set having the same identifier as the second network, the address of the first communication device is the destination address, and the address where the second communication device is connected to the first network is the source address A first packet is transmitted by describing a redirect instruction including an identifier of the second network that is the selected set of networks and an address at which the third communication device is connected to the second network in the proposal packet. When a proposal packet in which a redirect instruction is described is received, a communication packet transmitted from the first communication apparatus to the second communication apparatus is addressed to the address of the third communication apparatus described in the redirect instruction. And forwarding through the second network described in the redirect instruction.

( 5 ) In the communication method according to ( 4 ), the second network includes a management device for managing addresses of communication terminals and transfer devices connected to the second network, and the first communication device. The address of the management device is set in advance, and when the first communication device receives the proposal packet in which the redirect instruction is described, the identifier of the network instructed to redirect and the address of the redirect destination are read, An inquiry is made to the management apparatus corresponding to the network described in the redirect instruction whether the address described in the redirect instruction is managed, and the management apparatus returns a response to the inquiry from the first communication apparatus. The first communication device performs the first communication according to the redirect instruction according to the response result. Determines whether a communication packet to be transmitted from the device to the second communication device is transferred to the address of the third communication device described in the redirect instruction via the second network described in the redirect instruction. It is characterized by that.

(6) In a communication apparatus that performs packet communication, a first physical or logical interface connected to the first network or terminal, and a plurality of networks that are physically or logically different from the first network or terminal It has second to Nth (N is an integer greater than or equal to 3) interfaces to be connected. When a packet is received from the first interface, the routing table is searched and the output interface is selected from the second to Nth interfaces. A routing processor that forwards the packet via the determined output interface, and when there is no route information in the route table when transmitting the received packet , the second to Nth interfaces At least one of the source address of the packet and the second to Nth interfaces A search packet for notifying all the pairs of each identifier for identifying each of the addresses and a plurality of networks connected to the network, the search packet transmission unit to be transmitted to the destination of the packet, it received the search packet The address of the first communication device of the set having the same identifier as that of the network connected to the other communication device selected from the combination of the plurality of addresses included in the search packet and the identifier of the network is sent from another communication device. Proposal for receiving a proposal packet transmitted using the address connected to the selected network of other communication devices as the source address and reading the address of the other communication device described in the proposal packet Receives the address of the other communication device read from the packet receiver and the proposed packet receiver. And a route table creation unit for creating, adding, and correcting a route table.

  According to the present invention, large-scale routing information is not required by exchanging IP routing information necessary for the communication only between the communication device with which the communication device intends to communicate. In addition, the route can be easily selected. In addition, by exchanging routing information only with the communication apparatus on the other side, even if erroneous information is notified, the influence range does not reach the entire network.

  Furthermore, according to the present invention, in the exchange of routing information, the exchange process is simplified by using a network identifier. Also, in exchange of routing information, various protocols are supported by exchanging protocol information used for communication.

  Furthermore, according to the present invention, in the exchange of routing information, a magic number (random numerical value) is used to easily correspond to an inquiry and a response. Further, in the exchange of routing information, by making an inquiry to a management server in the network, communication using false information from a terminal unrelated to the network is rejected.

  As described above, by using the communication method and communication apparatus of the present invention, it becomes unnecessary to exchange routing information between a plurality of networks to which a certain user is connected. That is, each network can provide a connection service with a user independently of other networks.

  Further, it is not necessary for the communication apparatus of the present invention connected to a plurality of networks to transmit the routing information of other networks to the network using a dynamic routing protocol. That is, it is possible to prevent a situation in which the entire network is affected by erroneous routing information transmitted from the user side.

  In addition, the communication apparatus of the present invention does not transmit routing information from the network using a dynamic routing protocol, and only through which network the terminal communicates with another terminal through which the terminal communicates. You can discover if they can communicate with each other. That is, the communication apparatus of the present invention only needs to have the routing information without holding a huge amount of routing information, and can communicate easily.

  Furthermore, the network can be selected efficiently by including the network identifier in the proposed packet of the present invention.

  Furthermore, by including information related to the communication method in the search packet of the present invention, it becomes possible to efficiently exchange information regarding the route and information regarding the supported protocol.

  Furthermore, by including a randomly generated numerical value in the search packet of the present invention, the search packet and the proposed packet can be easily associated with each other, and an attack by an illegal proposed packet can be prevented.

  Furthermore, a communication device of the present invention designates a redirect to another communication device, and confirms that the destination of the redirect designation is a legitimate address, so that a terminal that does not belong to the network through which the search packet passes can be obtained. Communication is possible safely.

As described above, according to the present invention, the following intended object can be achieved by using the communication method and the communication apparatus as described above. That is,
(1) It is possible to solve the problem that it is impossible to connect to an external network using a plurality of lines in the conventional technique using a default route.

(2) Furthermore, when connecting to an external network using a plurality of lines, it is possible to solve the problem that the administrator needs to perform complicated settings such as communication path determination and routing protocol. Become.

(3) Further, by using the dynamic routing protocol, it is possible to solve the problem that a huge scale routing table needs to be held.

(4) Further, by using the dynamic routing protocol, it is possible to solve the problem that there is a possibility of affecting the entire network when erroneous routing information is notified.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.
In the first embodiment, the case where the communication apparatus operates as a router is described as an example. However, as will be apparent from the following description, the communication apparatus may be a terminal such as a personal computer. In addition, although the number of networks is described as 3, the number of networks is not limited to 3 as is clear from the following description.

  As shown in the figure, a terminal 1 is connected to three networks via a communication device 1 of the present invention. Similarly, the terminal 2 is connected to the networks 1 and 2 via the communication device 2 of the present invention, and the terminal 3 is connected to the networks 1 and 3 via the communication device 3 of the present invention.

  Here, the communication apparatus of the present invention is given an IP address from the network to which the own apparatus is connected. For example, the communication device 1 of the present invention is given IP addresses that can communicate with the networks from the networks 1, 2, and 3, respectively.

  However, the router belonging to a certain network does not need to know in advance what IP address is assigned to the communication apparatus 1 of the present invention from another network. For example, a route whose destination is the IP address 21 issued from the network 2 to the communication device 1 of the present invention is set in the routing table of routers (for example, the router 11, the router 12, and the router 13) belonging to the network 1. You don't have to.

  In the communication apparatus 1 of the present invention, the network 1 is a default network, and the terminal 1 is preset with an IP address capable of communicating with the network 1.

The same applies to the communication devices 2 and 3 and the terminals 2 and 3 of the present invention.
The communication method of the present invention when the terminal 1 communicates with the terminal 2 will be described.
First, the terminal 1 transfers an IP packet having the IP address of the terminal 2 as a destination and the IP address of the terminal 1 as a transmission source to the communication device 1 of the present invention.

  Upon receiving this IP packet, the communication device 1 of the present invention delivers the communication device 1 of the present invention from each network to an IP packet whose destination is the IP address of the terminal 2 and whose source is the IP address of the terminal 1. An IP packet (search packet) in which the current IP address is written is created and transferred to the network 1.

  Since the destination address is the address of the terminal 2, the search packet is transferred from the router 11 to the router 12 via the network 1, and is transferred from the router 12 to the communication device 2 of the present invention.

  The communication device 2 of the present invention that has received the search packet does not transfer the search packet to the terminal 2, and the IP address written in the packet by the communication device 1 of the present invention is issued from each network. read.

  The communication device 2 of the present invention has the read address as a destination for at least one or all of the read addresses, and the address that the communication device 2 of the present invention has been paid out from each network as a transmission source One or a plurality of IP packets (suggested packets) are created and transferred to the router of each network via the network to which the source IP address belongs.

  The one or more proposal packets are not necessarily IP addresses that can communicate with the network to which the destination is transferred. For example, when a proposal packet destined for the IP address 31 issued to the communication apparatus 1 of the present invention from the network 3 is transferred to the network 2, the IP address 31 does not exist in the routing table of the router in the network 2. Therefore, transfer is not possible.

  On the other hand, for example, when a proposal packet destined for the IP address 21 issued to the communication apparatus 1 of the present invention from the network 2 is transferred to the network 2, the proposal packet can be transferred by the network 2. It is transferred to the communication device 1 of the invention. Thus, some of the proposal packets transmitted by the communication device 2 of the present invention are transferred to the communication device 1 of the present invention.

  The communication device 1 of the present invention that has received the proposal packet reads the destination IP address and the source IP address of the proposal packet. With this operation, the communication apparatus 1 of the present invention can know the network that can be used for communication with the terminal 2 and the IP address of the communication apparatus 2 of the present invention. The communication device 1 of the present invention creates a route table as shown in FIG. 2 as a route of a packet addressed to the terminal 2. At this point, a route other than the network 1 reaching the terminal 2 has been discovered.

  Furthermore, the communication apparatus of the present invention selects one from a plurality of route sets in the route table shown in FIG. For example, when the route described in the third line is selected, a packet received by the communication device 1 of the present invention and having the terminal 1 as the transmission source and the terminal 2 as the destination is transmitted by the communication device 2 of the present invention to the network. 2 is transferred to the network 2 with the IP address 22 issued from 2 as the destination.

  When the communication apparatus of the present invention performs such an operation, the communication apparatus of the present invention connected to a plurality of networks without exchanging mutual routing information between the networks 1, 2, and 3 is connected to the network. The terminal tries to communicate without transmitting routing information of another network using a dynamic routing protocol, and without causing the communication device of the present invention to transmit routing information from the network using a dynamic routing protocol. Since it is possible to discover through which network the terminals can communicate with each other only with respect to a route with another terminal, communication is possible without holding enormous routing information.

  In addition, here, the case where the operation of transferring the IP packet from the terminal 1 to the terminal 2 is performed first has been described, but once the network through which the above operation has been determined is determined, the IP packet arrives. It is not necessary to perform the operation described above each time.

  In the communication apparatus and communication method of the present invention described in the first embodiment, the proposed packet may not necessarily reach the communication apparatus of the present invention on the other side. Therefore, in the second embodiment, a communication method and a communication device in which the proposed packet reaches the communication device of the present invention on the other side will be described.

  In the following description, it is assumed that the network configuration has the configuration shown in FIG. It is assumed that the IP address is set in the same manner as described in the first embodiment.

Here, the communication method of the present invention when the terminal 1 communicates with the terminal 2 will be described.
First, the terminal 1 transfers an IP packet having the IP address of the terminal 2 as a destination and the IP address of the terminal 1 as a transmission source to the communication device 1 of the present invention. Upon receiving this IP packet, the communication device 1 of the present invention delivers the communication device 1 of the present invention from each network to an IP packet whose destination is the IP address of the terminal 2 and whose source is the IP address of the terminal 1. An IP packet (search packet) in which an IP address and an identifier of each network are written is created and transferred to the network 1.

  That is, the search packet includes information as shown in the table of FIG. As in the first embodiment, since the destination address is the address of the terminal 2, the search packet is transferred from the router 11 to the router 12 via the network 1, and transferred from the router 12 to the communication apparatus 2 of the present invention. Is done.

  The communication device 2 of the present invention that has received the search packet does not transfer the search packet to the terminal 2, and the IP address written in the packet is the IP address from which the communication device 1 of the present invention is issued from each network. Read a set of network identifiers.

  The communication device 2 of the present invention searches the network to which the device itself is connected from the read network identifiers, and the network obtained by the search and the communication device 1 of the present invention connected to the network. Get the IP address. In this case, since the communication apparatus 2 of the present invention is connected to the network 1 and the network 2, the first and second lines in the table of FIG. 3 are read and the third line is ignored.

  Furthermore, the communication device 2 of the present invention has the read address as a destination for at least one or all of the obtained sets, and the communication device 2 of the present invention is paid out from the network corresponding to the address. One or a plurality of IP packets (suggested packets) having the address as a transmission source are created and transferred to the router of each network via the network to which the transmission source IP address belongs.

  That is, in this case, one or two of the two proposed packets (destination IP address, source IP address) = (IP address 11, IP address 12), (IP address 21, IP address 22) are transmitted. To do. However, since the former proposal packet is a route that has already received the search packet, it is self-evident and there is no need to send the proposal packet.

  By using such a search packet and a proposal packet, as described in the first embodiment, a situation in which the destination is not necessarily an IP address capable of communicating with the transferred network is not caused. For example, a proposal packet of (destination IP address, source IP address) = (IP address 21, IP address 22) must reach the communication apparatus 1 of the present invention via the network 2.

  The operation of the communication device 1 of the present invention that has received the proposal packet is the same as the operation described in the first embodiment.

  When the communication apparatus of the present invention performs such an operation, the communication apparatus of the present invention connected to a plurality of networks without exchanging mutual routing information between the networks 1, 2, and 3 is connected to the network. The terminal tries to communicate without transmitting routing information of another network using a dynamic routing protocol, and without causing the communication device of the present invention to transmit routing information from the network using a dynamic routing protocol. Since it is possible to discover through which network the terminals can communicate with each other only with respect to a route with another terminal, communication is possible without holding enormous routing information. Furthermore, information can be efficiently exchanged by using only the minimum number of proposal packets.

  In addition, here, the case where the operation of transferring the IP packet from the terminal 1 to the terminal 2 is performed first has been described, but once the network through which the above operation has been determined is determined, the IP packet arrives. It is not necessary to perform the operation described above each time.

  The communication apparatus and the communication method of the present invention described in the first and second embodiments, when transferring a packet from the terminal 1 to the terminal 2 after determining the path, for example, a plurality of path tables shown in FIG. When the route described in the third row is selected from the set of routes, the packet received by the communication device 1 of the present invention and having the terminal 1 as the transmission source and the terminal 2 as the destination is the communication device 2 of the present invention. Needs to be transferred to the network 2 with the IP address 22 issued from the network 2 as the destination.

  In this case, as a communication protocol between the communication apparatuses 1 and 2 of the present invention, a method of simply converting the IP address described in the header of the IP packet going from the terminal 1 to the terminal 2 into the address of the communication apparatus of the present invention ( A method using NAT) and a method of encapsulating and transferring an IP packet from the terminal 1 to the terminal 2 into an IP packet directed from the communication apparatus 1 to the communication apparatus 2 of the present invention (when using a tunnel). Furthermore, when using tunnels, there are various types of tunnel technologies such as IP in IP and IPSec, and communication may not be possible if the other side does not support some methods.

Thus, in the third embodiment, a method and a communication apparatus that perform negotiation using a method before communication and perform communication using a method corresponding to the other party will be described.
The network configuration will be described as having the configuration shown in FIG. It is assumed that the IP address is set in the same manner as described in the first embodiment.

Hereinafter, the communication method of the present invention when the terminal 1 communicates with the terminal 2 will be described.
First, the terminal 1 transfers an IP packet having the IP address of the terminal 2 as a destination and the IP address of the terminal 1 as a transmission source to the communication device 1 of the present invention. Upon receiving this IP packet, the communication device 1 of the present invention delivers the communication device 1 of the present invention from each network to an IP packet whose destination is the IP address of the terminal 2 and whose source is the IP address of the terminal 1. An IP packet (search packet) in which the IP address, the identifier of each network and the corresponding method are written is created and transferred to the network 1.

  That is, the search packet includes information as shown in the table of FIG. As in the first embodiment, since the destination address is the address of the terminal 2, the search packet is transferred from the router 11 to the router 12 via the network 1, and transferred from the router 12 to the communication apparatus 2 of the present invention. Is done.

  The communication device 2 of the present invention that has received the search packet does not transfer the search packet to the terminal 2, and the IP address written in the packet is the IP address from which the communication device 1 of the present invention is issued from each network. Read a set of network identifiers and corresponding schemes.

  The communication device 2 of the present invention searches the network to which the device itself is connected from the read network identifiers, and the network obtained by the search and the communication device 1 of the present invention connected to the network. Get the IP address and corresponding scheme. In this case, since the communication apparatus 2 of the present invention is connected to the network 1 and the network 2, the first and second lines of the table shown in FIG. 4 are read and the third line is ignored.

  Furthermore, the communication device 2 of the present invention compares the read result with the method supported by each device in each network. For example, if the communication apparatus 2 of the present invention is compatible with NAT and not IP in IP, the first line of the route table shown in FIG. 4 is ignored and the second line is read.

  Furthermore, the communication device 2 of the present invention has the read address as a destination for at least one or all of the obtained sets, and the communication device 2 of the present invention is paid out from the network corresponding to the address. Create one or more IP packets (suggested packets) with the address as the sender and the method that the device supports, and forward it to the router of each network via the network to which the sender's IP address belongs .

  That is, in this example, one proposal packet of (destination IP address, transmission source IP address, method) = (IP address 21, IP address 22, NAT) is transmitted. Naturally, the proposed packet passing through the network 1 is self-evident because it is a route that has already received the search packet, as in the second embodiment, and it is not necessary to send the proposed packet.

  By using such a search packet and a proposal packet, it becomes possible to simultaneously select a network and a method.

  The operation of the communication device 1 of the present invention that has received the proposal packet is the same as that described in the first and second embodiments. The communication device 1 of the present invention communicates with the communication device 2 of the present invention using the method proposed in the proposed packet.

  When the communication apparatus of the present invention performs such an operation, the communication apparatus of the present invention connected to a plurality of networks without exchanging mutual routing information between the networks 1, 2, and 3 is connected to the network. The terminal tries to communicate without transmitting routing information of another network using a dynamic routing protocol, and without causing the communication device of the present invention to transmit routing information from the network using a dynamic routing protocol. Since it is possible to discover through which network the terminals can communicate with each other only with respect to a route with another terminal, communication is possible without holding enormous routing information. Furthermore, by notifying the communication method, it is possible to efficiently exchange information on the route and information on the supported protocol.

  In addition, here, the case where the operation of transferring the IP packet from the terminal 1 to the terminal 2 is performed first has been described, but once the network through which the above operation has been determined is determined, the IP packet arrives. It is not necessary to perform the operation described above each time.

  In the communication method and apparatus of the present invention described in the first to third embodiments of the present invention, for example, when communication from the terminal 1 to the terminal 2 and communication from the terminal 1 to the terminal 3 occur at the same time, The communication device 1 receives the proposal packet almost simultaneously from the communication devices 2 and 3 of the present invention, and there is a problem that it is difficult to associate the search packet with the proposal packet.

  Further, when a malicious user indiscriminately transmits a proposal packet and the communication device of the present invention receives it, there is a possibility that the communication device of the present invention selects a route that has been missed.

  Therefore, in the fourth embodiment, a communication method and apparatus according to the present invention that takes a correspondence between a search packet and a proposed packet will be described. The network configuration will be described as having the configuration shown in FIG. It is assumed that the IP address is set in the same manner as described in the first embodiment.

Hereinafter, the communication method of the present invention when the terminal 1 communicates with the terminal 2 will be described.
First, the terminal 1 transfers an IP packet having the IP address of the terminal 2 as a destination and the IP address of the terminal 1 as a transmission source to the communication device 1 of the present invention. Upon receiving this IP packet, the communication device 1 of the present invention randomly selects the search packet described in the first to third embodiments with the IP address of the terminal 2 as the destination and the IP address of the terminal 1 as the transmission source. Send the selected number.

  The communication device 2 of the present invention that has received the search packet reads the random numerical value from the search packet, assigns the read value to the proposal packet, and proposes by the operation described in the first to third embodiments. Forward the packet.

  The communication device 1 of the present invention that has received the proposal packet reads the random numerical value from the proposal packet, and when the read numerical value is the same value as the value included in the search packet transmitted by the own device. Performs the operation described in the first to third embodiments, and ignores the proposed packet if the values are different.

  When the communication apparatus of the present invention performs such an operation, the communication apparatus of the present invention connected to a plurality of networks without exchanging mutual routing information between the networks 1, 2, and 3 is connected to the network. The terminal tries to communicate without transmitting routing information of another network using a dynamic routing protocol, and without causing the communication device of the present invention to transmit routing information from the network using a dynamic routing protocol. Since it is possible to discover through which network the terminals can communicate with each other only with respect to a route with another terminal, communication is possible without holding enormous routing information. Further, the search packet and the proposed packet can be associated with each other by the operation as described above, and it is possible to avoid the erroneous operation of the communication apparatus of the present invention due to the attack using the proposal packet by the malicious user.

  In the communication method and apparatus of the present invention described in the first to fourth embodiments of the present invention, the communication apparatus of the present invention communicates with a terminal not connected to the network 1 in order to transfer the search packet to the network 1. Can not do it. In contrast, in this embodiment, the communication method of the present invention enables communication with a terminal that does not belong to the network through which the search packet passes, by designating a redirect to another communication device by a communication device of the present invention. The communication device will be described.

FIG. 5 is a diagram illustrating a network configuration according to the fifth embodiment.
As shown in the figure, a terminal 1 is connected to two networks via a communication device 1 of the present invention. Similarly, the terminal 2 is connected to the network 1 via the communication device 2 of the present invention, and the terminal 3 is connected to the network 3 via the communication device 3 of the present invention.

  Here, the communication apparatus of the present invention is given an IP address from the network to which the own apparatus is connected. For example, the communication apparatus 1 of the present invention is given IP addresses that can communicate with the respective networks from the networks 1 and 2.

  However, the router belonging to a certain network does not need to know in advance what IP address is assigned to the communication apparatus 1 of the present invention from another network. For example, a route whose destination is the IP address 21 issued from the network 2 to the communication device 1 of the present invention is set in the routing table of routers (for example, the router 11, the router 12, and the router 13) belonging to the network 1. You don't have to.

In the communication apparatus 1 of the present invention, the network 1 is a default network, and the terminal 1 is preset with an IP address capable of communicating with the network 1.
The same applies to the communication devices 2 and 3 and the terminals 2 and 3 of the present invention.

A communication method of the present invention when the terminal 1 communicates with the terminal 3 will be described.
First, the terminal 1 transfers an IP packet having the IP address of the terminal 2 as a destination and the IP address of the terminal 1 as a transmission source to the communication device 1 of the present invention. Upon receiving this IP packet, the communication device 1 of the present invention delivers the communication device 1 of the present invention from each network to an IP packet whose destination is the IP address of the terminal 2 and whose source is the IP address of the terminal 1. An IP packet (search packet) in which an IP address and an identifier of each network are written is created and transferred to the network 1. That is, the search packet includes information as shown in the table of FIG.

  As in the first embodiment, since the destination address is the address of the terminal 2, the search packet is transferred from the router 11 to the router 12 via the network 1, and transferred from the router 12 to the communication apparatus 2 of the present invention. Is done. Here, as described in the third and fourth embodiments, the search packet may include information on the communication method and random numerical values.

  The communication device 2 of the present invention that has received the search packet does not transfer the search packet to the terminal 2, and the IP address written in the packet is the IP address from which the communication device 1 of the present invention is issued from each network. Read a set of network identifiers.

  The communication device 2 of the present invention searches for a preset network from the read network identifiers, and the network obtained by the search and the IP of the communication device 1 of the present invention connected to the network. Get an address.

  Here, it is assumed that the communication apparatus 2 of the present invention is preset with information regarding the network 2, the communication apparatus 3 of the present invention connected thereto, and the terminal 3. In this case, the communication device 2 of the present invention extracts information related to the network 2 from the set of the IP address and the network identifier described in the search packet.

  Furthermore, the communication device 2 of the present invention uses the read address as a destination for at least one or all of the obtained information sets, and the communication device 2 of the present invention pays out from the network corresponding to the address. One or a plurality of IP packets (suggested packets) having the address as a transmission source are created and transferred to the router of each network via the network to which the transmission source IP address belongs. About this proposal packet, the communication apparatus 3 of the present invention includes the IP address 23 given from the network 2 and the identifier of the network 2 as a redirect transfer destination.

  Upon receiving the proposal packet, the communication device 1 of the present invention reads the IP address and network identifier that are the redirect transfer destination described in the proposal packet. By this operation, when communicating with the terminal 2, the communication device 1 of the present invention knows that the same communication is possible by communicating with the terminal 3. For example, when the terminal 2 is a WEB server, this corresponds to a case where the terminal 2 instructs communication to the terminal 3 that is a mirror server as a redirect destination.

  When the terminal 1 communicates with the terminal 3 by such an operation, in the case of the present embodiment, the communication device 1 of the present invention uses the route as shown in FIG. Create a table.

  Furthermore, the communication device of the present invention is configured to receive a packet received by the communication device 1 of the present invention and having the terminal 1 as the transmission source and the terminal 2 as the destination, and the IP address from which the communication device 3 of the present invention has been issued from the network 2. The address 23 is transferred to the network 2 as a destination.

  In the case where the search packet includes the random numerical values described in the fourth embodiment, and the proposed packet does not include the same numerical value, the communication device 1 of the present invention performs the operation of ignoring the proposed packet. You may go.

  The communication device of the present invention performs such an operation, so that the communication device of the present invention connected to a plurality of networks does not exchange the routing information between the networks 1 and 2, and other networks The communication device of the present invention does not transmit the routing information of the network using the dynamic routing protocol, and the communication device of the present invention does not transmit the routing information from the network using the dynamic routing protocol. Since only the route between the terminals can be discovered through which network the terminals can communicate with each other, communication is possible without holding enormous routing information. Furthermore, when a communication device according to the present invention designates redirection to another communication device, it is possible to communicate with a terminal that does not belong to the network through which the search packet passes.

  In addition, here, the case where the operation of transferring the IP packet from the terminal 1 to the terminal 2 is performed first has been described, but once the network through which the above operation has been determined is determined, the IP packet arrives. It is not necessary to perform the operation described above each time.

  In the fifth embodiment, the method in which the communication device 2 of the present invention issues a redirect instruction to the terminal 3 when performing communication with the terminal 2 has been described. However, when the redirect instruction by the proposal packet has an illegal content, there is a possibility that the redirect is made to an irrelevant terminal. Therefore, in this embodiment, a communication method for installing a server for managing a network in each network and confirming whether the redirect destination is a terminal that is properly managed by the administrator of the network will be described.

FIG. 7 is a diagram illustrating a network configuration according to the sixth embodiment.
Similarly to the case described in the fifth embodiment, the terminal 1 is connected to the two networks via the communication device 1 of the present invention. Similarly, the terminal 2 is connected to the network 1 via the communication device 2 of the present invention, and the terminal 3 is connected to the network 2 via the communication device 3 of the present invention. Further, a management server 1 and a management server 2 are connected to the networks 1 and 2, respectively, and each management server manages the IP addresses of communication devices and terminals connected to the respective networks.

  Here, the communication apparatus of the present invention is given an IP address from the network to which the own apparatus is connected. For example, the communication apparatus 1 of the present invention is given IP addresses that can communicate with the respective networks from the networks 1 and 2.

  However, the router belonging to a certain network does not need to know in advance what IP address is assigned to the communication apparatus 1 of the present invention from another network. For example, a route whose destination is the IP address 21 issued from the network 2 to the communication device 1 of the present invention needs to be set in the routing table of routers (for example, the router 11 and the router 12) belonging to the network 1. There is no.

  In the communication apparatus 1 of the present invention, the network 1 is a default network, and the terminal 1 is preset with an IP address capable of communicating with the network 1.

The same applies to the communication devices 2 and 3 and the terminals 2 and 3 of the present invention.
First, the terminal 1 transfers an IP packet having the IP address of the terminal 2 as a destination and the IP address of the terminal 1 as a transmission source to the communication device 1 of the present invention. Upon receiving this IP packet, the communication device 1 of the present invention delivers the communication device 1 of the present invention from each network to an IP packet whose destination is the IP address of the terminal 2 and whose source is the IP address of the terminal 1. An IP packet (search packet) in which the IP address and the identifier of each network are written is created and transferred to the network 1.

  That is, the search packet includes information as shown in the table of FIG. As in the first embodiment, since the destination address is the address of the terminal 2, the search packet is transferred from the router 11 to the router 12 via the network 1, and transferred from the router 12 to the communication apparatus 2 of the present invention. Is done. Here, as described in the third and fourth embodiments, the search packet may include information on the communication method and random numerical values.

  The communication device 2 of the present invention that has received the search packet does not transfer the search packet to the terminal 2, and the IP address written in the packet is the IP address from which the communication device 1 of the present invention is issued from each network. Read a set of network identifiers.

  The communication device 2 of the present invention searches for a preset network from the read network identifiers, and the network obtained by the search and the IP address of the communication device 1 of the present invention connected to the network. Get. Here, it is assumed that the communication apparatus 2 of the present invention is preset with information regarding the network 2, the communication apparatus 3 of the present invention connected thereto, and the terminal 3.

  In this case, the communication device 2 of the present invention extracts information related to the network 2 from the set of the IP address and the network identifier described in the search packet.

  Furthermore, the communication device 2 of the present invention uses the read address as a destination for at least one or all of the obtained information sets, and the communication device 2 of the present invention pays out from the network corresponding to the address. One or a plurality of IP packets (suggested packets) having the address as a transmission source are created and transferred to the router of each network via the network to which the transmission source IP address belongs. About this proposal packet, the communication apparatus 3 of the present invention includes the IP address 23 given from the network 2 and the identifier of the network 2 as a redirect transfer destination.

Upon receiving the proposal packet, the communication device 1 of the present invention reads the IP address and network identifier that are the redirect transfer destination described in the proposal packet. By this operation, when communicating with the terminal 2, the communication device 1 of the present invention knows that the same communication is possible by communicating with the terminal 3. For example, when the terminal 2 is a WEB server, this corresponds to a case where the terminal 2 instructs communication to the terminal 3 that is a mirror server as a redirect destination.
Up to this point, the communication method described in the fifth embodiment is the same.

  Further, the communication device 1 of the present invention makes an inquiry to the management server 2 registered in advance in the communication device 1 of the present invention with respect to the read terminal 3 or the IP address of the communication device 3 of the present invention. When the management server 2 receives the inquiry, it responds to the inquiry.

  The response includes an answer as to whether the IP address of the terminal 3 to be inquired or the communication device 3 of the present invention is a regular address registered in the management server 2. Further, the response may include additional information such as information on payout of the IP address to be inquired and information on the user of the address.

  The communication device 1 of the present invention that has received the response, when the reply in the response is not a regular address or when the communication device 1 of the present invention determines that the additional information is illegal, Ignore redirect instructions. This operation prevents an action to establish communication with an illegally installed terminal by an illegal redirect instruction. If the reply in the response is a regular address, communication is performed using the same communication method as that described in the fifth embodiment.

  That is, the communication device 1 of the present invention creates a route table as shown in FIG. 6 as a route of a packet addressed to the terminal 3. Further, the communication device 1 of the present invention has received the packet received by the communication device 1 of the present invention and having the terminal 1 as the transmission source and the terminal 2 as the destination from the network 2. Transfer to the network 2 with the IP address 23 as the destination.

  In the case where the search packet includes the random numerical values described in the fourth embodiment, and the proposed packet does not include the same numerical value, the communication device 1 of the present invention performs the operation of ignoring the proposed packet. You may go.

  When the communication apparatus of the present invention performs such an operation, the communication apparatus of the present invention connected to a plurality of networks without exchanging mutual routing information between the networks 1, 2, and 3 is connected to the network. The terminal tries to communicate without transmitting routing information of another network using a dynamic routing protocol, and without causing the communication device of the present invention to transmit routing information from the network using a dynamic routing protocol. Since it is possible to discover through which network the terminals can communicate with each other only with respect to a route with another terminal, communication is possible without holding enormous routing information.

  In addition, a communication device of the present invention designates redirection to another communication device, and by confirming that the destination of the redirection designation is a regular address, a terminal that does not belong to the network through which the search packet passes can be obtained. Communication is possible safely.

  In addition, here, the case where the operation of transferring the IP packet from the terminal 1 to the terminal 2 is performed first has been described, but once the network through which the above operation has been determined is determined, the IP packet arrives. It is not necessary to perform the operation described above each time.

  In the seventh embodiment, the configuration of the communication apparatus described in the first to sixth embodiments will be described.

  FIG. 8 is a diagram showing a configuration example of the communication apparatus of the present invention, and FIG. 9 is a flowchart for explaining the operation.

  As shown in FIG. 8, the communication device 50 of the present invention includes a terminal-side interface 51, a network-side interface 52, a routing processing unit 53, a route table 54, a search packet transmitting unit 55, a proposed packet receiving unit 56, and a route table creating unit. 57.

  First, when the communication device 50 of the present invention receives a packet from the terminal side at the terminal side interface 51 (step S10), the routing processing unit 53 searches the route table 54 (step S11). As a result, when there is information on the destination of the received packet on the route table 54, the routing processing unit 53 transfers the received packet to the network side interface 52 in accordance with the contents of the route table 54 (step). S12).

  When there is no information about the destination of the received packet in the route table 54, the routing processing unit 53 temporarily stores the received packet, and the search packet transmission unit 55 transmits the search packet from the network side interface 52. The proposed packet receiver 56 waits for a certain time (step S13).

  If the proposed packet receiver 56 receives the proposed packet from the network side interface 52 within the predetermined time, the proposed packet receiver 56 determines the content (step S14). In this determination processing, the determination regarding the matching of the communication methods described in the third embodiment, the determination regarding the matching of the random numerical values described in the fourth embodiment, and whether or not the redirection described in the fifth and sixth embodiments is possible. A determination may be included.

  If the determination is further OK, the proposed packet receiver 56 notifies the route table generator 57 of the contents of the proposed packet. Upon receiving the notification, the route table creation unit 57 creates the route table 54 or adds or corrects the contents (step S15), and the routing processing unit 53 transfers the temporarily stored packet according to the contents of the route table 54 (step S15). S12).

  When the proposed packet receiving unit 56 does not receive the proposed packet within the predetermined time, or when the determination at the proposed packet receiving unit 56 is NG, the proposed packet receiving unit 56 57, the result of non-reception of the proposal packet or determination NG is notified.

  The route table creation unit 57 that has received the notification adds a default route to the route table 54 as a route to the destination of the received packet (step S16). Further, the routing processing unit 53 transfers the temporarily stored packet to the default route according to the contents of the route table 54 (step S12).

  By using the communication device 50 of the present invention as described above, communication by the communication method described in the first to sixth embodiments is possible.

It is a figure which shows the structure of the network in Example 1, 2, 3, 4 of this invention. FIG. 10 is a diagram illustrating an example of a route table in the first embodiment. It is a figure which shows the example of the table in Example 2. FIG. It is a figure which shows the example of the table in Example 3. FIG. FIG. 10 is a diagram illustrating a network configuration according to a fifth embodiment. FIG. 20 is a diagram illustrating an example of a route table in the fifth embodiment. FIG. 10 is a diagram illustrating a network configuration according to a sixth embodiment. It is a structural example of the communication apparatus in this invention. It is a flowchart for demonstrating operation | movement of the communication apparatus in this invention. It is a figure which shows the structural example of the conventional network. It is a figure which shows the example of the conventional routing table. It is a figure which shows the example of the table in Example 5. FIG.

Explanation of symbols

50: Communication device 51: Terminal side interface 52: Network side interface 53: Routing table 54: Route table 55: Search packet transmission unit 56: Proposed packet reception unit 57: Route table creation unit

Claims (6)

Communication in which the first communication device and the second communication device are physically or logically connected to a plurality of networks, respectively, and the first communication device and the second communication device perform packet communication via the network. In the method
When the first communication device transmits a communication packet, the first communication device identifies the source address of the communication packet, and each address of the own device connected to the plurality of networks and the plurality of networks. A search packet notifying all pairs of identifiers is transmitted toward the destination of the communication packet,
When the second communication device receives the search packet, the second communication device reads a set of an address and a network identifier that the first communication device is connected to the network from the search packet, and the second communication device reads the second packet from the set. Selecting at least one set having the same identifier as the network to which the communication device is connected,
The proposed packet with the address of the first communication device of the selected set as the destination address and the address where the second communication device is connected to the network of the selected set as the source address is selected. Send through a pair of networks,
When the first communication device receives the proposal packet, the first communication device reads the address of the second communication device described in the proposal packet;
A communication method for transferring a communication packet to be transmitted from the first communication device to the second communication device with the read address of the second communication device as a destination. The communication method according to claim 1 ,
The search packet describes a set of an address and a communication protocol with which the first communication device is connected to the network, and the first communication device is connected to the second communication device according to the described communication protocol. And the protocol used when communicating with the corresponding network,
The communication method, wherein the second communication device also reads a communication protocol described in the search packet and performs communication only with a communication protocol supported by the own device. The communication method according to claim 1 or 2 ,
In the search packet, a numerical sequence created by the first communication device is described. When the second communication device receives the search packet, the second communication device reads the numerical sequence and reads the numerical sequence in the proposal packet. A communication method characterized in that a numerical sequence is described and transmitted. A first communication device is physically or logically connected to a plurality of networks, a second communication device connected to the first network, and a third communication device connected to the second network In a communication method for performing packet communication with
When the first communication device transmits a communication packet that communicates with the second communication device, the source address of the communication packet and each address at which the device is connected to the plurality of networks And transmitting a search packet notifying all sets of identifiers for identifying the plurality of networks,
When the second communication device receives the search packet, the second communication device reads a set of an address and a network identifier that the first communication device is connected to the network from the search packet. Selecting at least one set having the same identifier as the second network to which the communication device is connected,
The proposed packet having the address of the first communication device as a destination address and the address where the second communication device is connected to the first network as a source address is the network of the selected set A second network identifier and a redirect instruction including an address at which the third communication device is connected to the second network are described and transmitted ;
Before SL first communications device, when receiving a proposal packet the redirect instruction is described, is described a communication packet transmitted from the first communication device to the second communication device to the redirect instruction A communication method, wherein the address of the third communication device is used as a destination and is transferred via the second network described in the redirect instruction. The communication method according to claim 4 , wherein
A management device for managing addresses of communication terminals and transfer devices connected to the second network in the second network;
In the first communication device, the address of the management device is set in advance,
When the first communication device receives a proposal packet in which the redirect instruction is described, the first communication device reads an identifier of the redirected network and a redirect destination address, and corresponds to the network described in the redirect instruction. Ask the management device whether the address described in the redirect instruction is managed,
The management device responds to an inquiry from the first communication device,
According to the result of the response, the first communication device transmits a communication packet to be transmitted from the first communication device to the second communication device according to the redirect instruction. A communication method characterized by determining whether or not to transfer via the second network described in the redirect instruction, with the address of the device as a destination. In a communication device that performs packet communication,
A physical or logical first interface connected to the first network or terminal, and second to Nth (N is three) connected to a plurality of networks physically or logically different from the first network or terminal. An integer) interface,
A routing process in which a routing table is searched when a packet is received from the first interface, an output interface is determined from the second to Nth interfaces, and the packet is transferred via the determined output interface And
When transmitting the received packet, if there is no route information in the route table, the source address of the packet from at least one of the second to Nth interfaces, and the second to Nth A search packet transmitting unit for transmitting a search packet for notifying all sets of identifiers for identifying each of the addresses connected to the plurality of networks and the identifiers to the destination of the packet When,
From the other communication device that has received the search packet, the set having the same identifier as the network to which the other communication device selected from the set of a plurality of addresses and network identifiers included in the search packet is connected Received a proposal packet transmitted using the address of the first communication device as a destination address and the other communication device connected to the selected set of networks as a source address, and described in the proposal packet A proposed packet receiving unit that reads an address of the other communication device ,
A communication apparatus comprising: a route table creation unit that receives the address of the other communication device read from the proposal packet reception unit and creates, adds, and corrects the route table.

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